Renewable fuse



F'. C. LA MAR RENEWABLE FUSE May 17, 1932.

Filed March 23, 1928 VIII/II I /xx/ NVENTOR J( &(2 04:

Patentecl May 17, 1932 I UNITED STATES PATENT OFFICE FRANK C. LA. MAR, OF NEW YORK, N. Y., ASSIGNOR TO GREAT WESTERN FUSE COMPANY,

' OF PITTSBURGH, PENNSYLVANIA, A CORPOR-ATION OF DELAVVARE RENEWABLE FUSE Application. filed March 23, 1928. Serial No. %4,138.

The object which I have in View is the provision of a new and improved renewable :fuse which is of simple and nexpensive, yet

durable Construction, which may be easily assembled and disassembled without reqniring skill, and which will be safe and efficent in service.

In the accompanying drawings, wherein I have illustrated the best embodiments of the principles of my invention now known to me, Fig. 1 is a longitudinal section of the fuse.

Fig. 2 is a broken elevation showing one end of the fuse with the screw cap removed. Fig. 3 is an end View of the same end of the fuse with the screw cap removed.

Fig. 4 is an inner face view of the slotted washer.

Fiq. 5 is an elevation showing the two terminal blades connected by the fusible link, the closure disk fixedly mounted on one blade and the slotted Washer and dowel applied to the other blade.

Fig. 6 is an elevation of the left hand terminal blade in Fig. 1.

Fig. 7 is an end view of one of the ferrules.

Fig. 8 is a detail showing the dowel-pin.

Referring to the drawings, 1 represents the cylindrical shell which may be of insulating material, such as fibre.

A metal' ferrule 2 is fixed on each end of the shell 1 as by threaded engagement and riveting. The .shell and ferrules comprise the tubular body of the fuse.

The ferrules 2 are provided at their ends with recesses 3 which form seats and which are preferably in diametrically opposed pairs.

4 and 5 are the metall-ic terminal blades having reduced inner ends to which are detachably Secured the ends of the fusible link 6.

One of the terminal blades, the right hand blade 4 in Fig. 1, has fixedly mounted thereon the metal circular closure head 7 which is arranged to fit on the end of the corresponding ferrule 2. The head 7 is provided with a diametrically disposecl rib 8 on its inner face whose ends engage the seats 3 to prevent relative rotation betwen the head and the fuse body.

An annular screw cap 9 is screwed onto eX- ternal threads on the ferrule to clamp the ead fiXedly in'position relative to the fuse ody.

The other blade 5 is provided with a fixed abutment or plate 10 which when the fuse is assembled lies slightly within the outer end of the corresponding ferrule 2.

11 represents a slotted washer which slips down over the end of the blade 5 and fits against the end of the ferrule 2. The inner face of the washer 11 is provided with arcuate shoulders 12 which fit down into the end of the ferrule and also with diametrically opposed lugs 13 which engage the seats 3 in the end of the corresponding'ferrule 2. When in place the slotted washer engages the abutment 10 of the blade 5.

The blade 5 is also provided with a tra11sversely disposed hole 14 in which is driven the dowel-pin 15 to hold the washer 11 in place against the abutment 10 of the blade 5.

I prefer to give the hole 14 a taper from one end to the other and to taper the dowel pn 15 so as to impart an inwardly exerted wedging action on the washer 11 to force it into snug engagement with the abutment 10 and thus seal the edges of the slot in the washer 11 against the outward escape of flame along the blade.

The parts are clamped rigidly in position by means of the annular screw cap 9 which is screwed onto the exterior threads of the ferrule 2.

The cap also prevents the dislodgment of the dowel pin by longitudinal movement thereof.

To assemble the fuse, the assembled terminal blades and fusible link are inserted into the fuse body from the right end in Fig. 1 until the closure head 7 of the blade 4 rests against the end of the ferrule With its rib 8 engaging the ferrule seats 3. The corresponding screw cap 9 is then applied and tightened. The slotted washer 11 is then slipped down over the other blade 5 until lts lugs 1.3 engage the seats 3 in the end of the ferrule 2.

The dowel 15 is then driven into the hole 14 to tighten the slotted Washer 11 against the abutment 10 of the blade 5, and the corresponding screw cap 9 is then screwed onto the ferrule to hold the parts against relative movement.

To disassemble the fuse the screw cap 9 on the left end of the fuse in Fig. 1 is first removed, the dowel is driven out and the slotted washer slipped ofl' the end of the blade 5.

The other screw cap is then removed and the blade 4 and the parts attached thereto may then be lifted ofi.

It is evident from the foregoing that my renewable fuse is extremely simple in con: struction, conprising a minimum number of separate parts. It is thus inexpensive to manufacture.

It is easily and quickly assembled and disasembled without requiring skill or special tools.

Furthermore it is eflicient, as the fusion of the fusible link is not attended by the outward travel of flames along the blade, because the slotted washer 11 is wedged and clamped down snugly onto the' abutment 10 which seals the edges of the slot in the washer.

What I desire to claim is 1. In a renewable fuse', the combination of a tubular body formed of nsulating material, a metal ferrule fixed on the end of said body and provided with a pair of diametrically opposed notches in its outer end, said ferrule also having screw threads on its outer surface, a blade terminal having a fixed abutment adjacent to its inner end and arranged to have the fusible link detachably connected to its inner end, said blade being also provided with a transversely extending hole, a washer provided with a transversely disposed slotted opening closed at both ends and arranged to be slid down over the blade and to rest against the end of the ferrule, said washer being provided with a rib to engage said notches to prevent relative rotative movement between the body and the terminal, a pin driven through said hole to secure said washer in place, and an annular cap screwed down onto said ferrule and having an inwardly extending annular fiange arranged to bear on said slotted washer.

2.' In a renewable fuse, the combination of a tubular body formed of insulating material, a metal ferrule fixed on the end of said body and provided with a pair of diametrically opposed notches in its outer end, said ferrule also having screw threads on its outer surface, a blade terminal having a fixed abutment adjacent to its inner end and arranged to have the fusible link detachably connected to its inner end, said blade beingalso provided with a transversely extencling hole tapering from one end to the other, a washer provided with a transversely disposed slotted opening closed at both ends and arranged to be slid down over the blade and to rest against the end of the ferrule, said washer being, proof March, 1928.

FRANK C. LA MAR. 

